CN111181625B - HTS satellite payload radio frequency domain implementation method based on N-active framework - Google Patents

Abstract

The implementation method of the HTS satellite payload in the radio frequency domain based on the N-active architecture is specifically: (1) Determine the frequency range of the feeder beam and the frequency range of the user beam according to the available frequency resources provided by each frequency band of the HTS satellite communication link. , design and calculate the maximum envelope BW of the working bandwidth of a single user beam; (2) determine that in the HTS satellite communication system, a single user beam is managed by several gateway stations; (3) carry out the HTS satellite load forward feed branch Design of the topology structure; (4) Design the topology structure of the feed-forward shunt synthesis network; (5) Design the payload scheme according to the feed-forward shunt synthesis network; (6) Carry out the HTS satellite payload return link feed Design of the electrical branch topology; (7) Design the return link branch combined network topology; (8) Design the payload scheme according to the return link branch combined network. The invention realizes the load scheme based on the N-active system architecture in the radio frequency field.

Description

Implementation method of HTS satellite payload in radio frequency domain based on N-active architecture

technical field

The invention belongs to the technical field of satellite payloads, and relates to a radio frequency domain realization method of satellite payloads.

Background technique

The high-throughput communication satellite system is multi-beam double-hop communication, and the general frequency planning is in the Ka-band. multimedia business. However, the rainfall attenuation in the Q/V frequency band is large. If the influence of the attenuation is overcome with a fixed system margin, it will cause a huge waste of power resources and increase the communication cost in clear sky. Complete compensation will degrade system performance and even cause communication interruption. If the traditional anti-rain fading method of uplink power modulation and adaptive coding adjustment is used, it can only provide 10-15dB channel compensation. These measures cannot meet the availability requirements of high-throughput satellites in the Q/V frequency band, so it must be adopted. other measures to compensate for rain attenuation.

Space diversity technology is an effective measure to solve the anti-rain fading of the channel. The existing high-throughput satellite communication system adopts the N+P system architecture to realize the space diversity. In this framework, the system mainly uses N gateways and has P backup gateways. Each primary gateway manages multiple user beams. When a certain gateway station is interrupted due to rain attenuation, it switches to the backup station for communication management of user beams. When the load implements the N+P system architecture, a loop switching matrix composed of mechanical switches is generally added at the feeder access end and the transmitter end to realize the gating of the main and standby gateways. The loss introduced by the switching matrix in the Ka frequency band will lead to G/T and EIRP drop by about 0.5dB, and the performance degradation caused by the switching matrix in the Q/V band will further increase to about 0.7dB.

In the Q/V frequency band, the spatial attenuation caused by the rain is severe, and the addition of backup stations to improve the system availability also increases the investment cost. The latest international research on the N-active intelligent gateway technology is a space diversity technology that is very suitable for anti-rain fading in the Q/V frequency band. However, the N-acitve system architecture adds extremely high complexity and great technical difficulty to the design of space satellite payloads, and has not yet been realized in engineering. At present, there is a trend in the world to use digital transparent forwarding (DTP) technology to realize the N-active system architecture, but DTP technology needs to realize the exchange communication between a user and multiple gateways in the satellite payload in the digital domain. The conversion of the Ka or Q/V feed frequency to the digital domain of the baseband frequency requires a lot of equipment. On the other hand, the channelized switching equipment that realizes digital transparent forwarding needs to process all frequencies of inbound and outbound feeders. For ultra-high-capacity satellite systems, the total processing bandwidth is between 50 and 100 GHz, and for very high-throughput communication systems. The bandwidth is above 200GHz. Such a large-scale bandwidth processing capability puts forward severe tests on the performance requirements of components, equipment weight, power consumption, and heat consumption. The manufacturing cost is also much higher than the general HTS communication load.

SUMMARY OF THE INVENTION

The technical problem solved by the present invention is: to overcome the deficiencies of the prior art, a method for realizing the radio frequency domain of the payload of an HTS satellite based on an N-active framework is provided, and in the radio frequency domain, the N-active system based on the branching and combining network technology is realized. The load scheme of the architecture, this scheme is realized by passive topology at the low power end, neither increasing power consumption and heat consumption, nor reducing the receiving quality parameter G/T and transmitting parameter EIRP of the load, making the N-active system architecture in The application can be realized in the HTS communication satellite.

The technical solution of the present invention is: an implementation method for the radio frequency domain of the payload of an HTS satellite based on an N-active framework, comprising the following steps:

(1) Determine the frequency range of the feeder beam and the frequency range of the user beam according to the available frequency resources provided by each frequency band of the HTS satellite communication link, and design and calculate the maximum envelope BW of the working bandwidth of a single user beam;

(2) Determine that in the HTS satellite communication system, a single user beam is managed by several gateway stations;

(3) carry out the design of the HTS satellite load forward feed shunt topology structure according to the conditions of steps (1) and (2);

(4) Design the topological structure of the feed-forward shunt synthesis network;

(5) Design the payload scheme according to the feed-forward shunt synthesis network;

(6) Carry out the design of the feeder branch topology of the HTS satellite payload return link;

(7) Design the return link branching synthesis network topology;

(8) Carry out the payload scheme design according to the return link split synthesis network.

In the step (2), the beam selection of a single user is managed together by 2-N gateway stations, where N is the total number of gateway stations.

The bandwidth of the single user beam is divided into N subbands, and the bandwidth of each subband is BW/N, that is, each gateway station provides a management resource with a bandwidth of BW/N for the user beam.

In the described step (3), carry out the design of the HTS satellite load forward feeder branch topology, specifically: assuming that the frequency of the user beam is F1, it enters from the feeder terminals of N gateway stations that manage the user. For the repeater system, for each gateway station, through the microwave multiplexer, F1 is divided into N sub-bands, and the corresponding frequencies are F1-1, F1-2, F1-3, ... F1-N, forming a feedforward Electrical Shunt Topology.

The forward feed-forward split-combination network topology or the return link split-combination network topology is implemented by a microwave hybrid bridge.

The described forward feeder branch synthesizing network topology structure is specifically: on the basis of the forward feeder branch topology structure, allocating and recombining N same-frequency feeder signals to synthesize N new F1 signals, Each newly synthesized F1 signal is composed of feed signals from N gateway stations.

The described design of the payload scheme according to the feed-forward shunt synthesis network is specifically:

(51) All user beam information received by each of the N gateway stations is divided into two parts of left-hand circular polarization and right-hand circular polarization according to different polarization modes. The user beam information is first filtered by the preselector to filter out the clutter and then sent to the low noise amplifier for amplification processing;

(52) The amplified user beam information is then split into multiple user sub-beams through a multiplexer, and the number of sub-beams and the number of user beams must satisfy: the number of sub-beams = the number of user beams * the gateway number of stations N;

(53) Combining the user sub-beam information of the same frequency and the same polarization mode from different gateway stations through the branch synthesis network to form one user beam information;

(54) The combined user beam information is subjected to signal amplification processing through the traveling wave tube amplifier, and then sent to the user end to complete the communication process.

The described design of the payload scheme according to the return link splitting synthesis network is specifically:

(81) The received user beam information is first filtered through a preselector and then sent to a low-noise amplifier for amplification, and then the amplified user beam information is divided into N parts by a multiplexer, and the beam information of different users is divided into N parts. split;

(82) combining the split sub-beams through a combiner according to user affiliation to form multiple user synthetic beams, and the number of synthetic beams is equal to the number of user beams;

(83) The user beam information is synthesized twice by the frequency converter and the combiner, and the combined user beam information is amplified through the amplifier, and then sent to the user end to complete the communication process.

The advantages of the present invention compared with the prior art are:

(1) The method of the present invention utilizes the characteristics of wide user beam bandwidth of the HTS satellite system to expand the granularity of signal branching, so that branching, filtering, switching, synthesis, etc. on the radio frequency become achievable technical paths. The frequency converter configured by this method is one-half of the DTP, and has low requirements for resources such as weight, power consumption, and heat consumption of the entire satellite. In addition, when the total feed bandwidth of multiple gateways surges to tens of GHz or even hundreds of GHz, DTP is limited by the performance of components, and multiple devices need to be configured to implement switching functions, resulting in extremely high platform requirements. And the method of the present invention is not limited to the device, and the development cost is far lower than the DTP technology at the same time;

(2) The present invention utilizes the branch synthesis network technology of the payload to realize the exchange communication between one user beam and multiple gateway stations in the HTS satellite communication system in the radio frequency domain, and realize the management of a single user beam by multiple gateway stations. This method does not need to be implemented in the digital domain, and can make N-active system architecture an achievable technology in VHTS systems on the order of Gbps. In the HTS satellite communication system using this technology, when the satellite-ground link increases the channel attenuation of the feeder link due to weather changes, the split-combination network technology configured by the on-board load can make the user beam and other gateway stations with good channels still remain. Maintain communication to ensure uninterrupted communication, minimize interference to user beam information, and greatly improve system availability;

(3) The principle of the method proposed by the present invention is clear and the planning is simple. On the one hand, it supports the deployment of early and gradual configuration of gateway stations, that is, the system operation can be performed by configuring a few gateway stations on the ground at the initial stage of system establishment, and with the increase of business volume in the follow-up period , and gradually configure more ground gateway stations to access the system to save operating costs; on the one hand, it can improve the system availability after the system is fully completed, keep the system communication uninterrupted during heavy rainfall, and the user link can still communicate; Appropriate switching paths are configured on the periphery of the synthetic branch network, and the system architecture is flexibly converted from N-active to N+P system architecture. For operators and users to enjoy good income and communication services in the early, middle and late stages of system construction;

(4) The method of the present invention divides a user beam into a plurality of user sub-beams, which are respectively handed over to a plurality of gateway stations for simultaneous management, and the user information is transmitted to a plurality of gateway stations. If a certain gateway station has a link In the case of interruption, only part of the user beam information is lost for a user beam, but this will not cause the connection between the user and the gateway station to be completely disconnected, and communication cannot be performed, which can effectively reduce the system interruption rate and improve the system availability. Spend.

(5) The method of the present invention can disperse the interruption or loss of the communication channel caused by severe rain attenuation, and disperse the continuous loss into multiple user sub-beams, so as to avoid the single user beam being caused by the loss of the communication channel. All communications for this user are interrupted. Since frequency division processing is performed on each user sub-beam, each user can still receive corresponding communication information. It ensures the communication quality of users and provides users with reliable on-board communication services.

Description of drawings

Fig. 1 is the flow chart of the method of the present invention;

Fig. 2 is a schematic diagram of the corresponding relationship between user beams and gateway stations when different system architectures are clear sky;

Fig. 3 is a schematic diagram of the communication bandwidth of two system architectures during rainfall;

Fig. 4 is the forward feed shunt topology diagram of the present invention;

Fig. 5 is the topological structure diagram of the present invention's feed-forward split-circuit synthesis network;

6 is a block diagram of the forward load design scheme of the present invention;

Fig. 7 is the return link branch topology diagram of the present invention;

Fig. 8 is the topology structure diagram of the combined network of the feed back branch according to the present invention;

FIG. 9 is a block diagram of the design scheme of the reverse load of the present invention.

Detailed ways

As shown in Figure 1, it is a flowchart of the method of the present invention, and the main steps are as follows:

Step 1: First perform frequency planning for the HTS satellite payload. Determine the frequency range of the feeder beam and the frequency range of the user beam according to the available frequency resources provided by the uplink and downlink frequency bands of the satellite communication link, and design and calculate the maximum envelope BW of the working bandwidth of a single user beam.

For different frequency bands, the ITU will have corresponding regulations on the frequencies used for communication, and the countries where the satellite coverage is located also have certain regulations. For the emerging HTS satellite system, when both feeders and users use the Ka-band, generally 29.5GHz-30GHz and 19.7GHz-20.2GHz are used for the user's uplink and downlink frequencies, and 27.5GHz-29.5GHz and 17.7GHz-19.7GHz are used for the user's uplink and downlink frequencies. Up and down frequencies for feeding.

Step 2: It is determined that in the HTS satellite communication system, a single user beam is managed by several gateway stations.

In an N-active system, assuming that there are N gateway stations in total, a single user beam can be selected to be managed by 2-N gateway stations together. If the number of gateways that manage a single user beam is N, the bandwidth of a single user beam is divided into N subbands, and the subbands can be divided into unequal bandwidths according to requirements. The bandwidth is BW/N, that is, each gateway station provides a management resource with a bandwidth of BW/N for the user beam.

The comparison of the N+P system architecture and the N-active system architecture in the clear sky state is shown in Fig. 2 (N=4). In the event of sudden heavy rain, the satellite-to-ground channel will be affected, and the quality of the communication link will be greatly reduced or even the link will be interrupted. In the N+P scheme, if the rain attenuation causes the link interruption of the gateway station communicating with the satellite, all the communication channels managed by the gateway station will be lost, that is, the entire user beam managed will be lost, and the network of the user terminal will be lost. All connections are disconnected and cannot communicate. In the N-active scheme, when a gateway station is affected by rain attenuation, all communication channels managed by the gateway station will also be lost. However, because a user beam bandwidth is divided into N subbands, only the gateway The sub-band managed by the station will have communication interruption, while the communication channels of other gateway stations will not be affected and can still communicate normally, that is, only a part (1/N) of the user beam bandwidth is lost for one user beam. , there is still (N-1)/N bandwidth capable of communication.

The comparison of the two schemes in the rain state is shown in Figure 3 (N=4). Calculated according to the N+P scheme, a gateway station manages multiple user beams. From the perspective of a single user beam, when the communication link is interrupted when affected by rain attenuation, the total capacity loss of the beam is 100 %. Calculate according to the N-active scheme, assuming N=4, that is, there are 4 gateway stations managing the same user beam at the same time, then under the influence of rain attenuation, the communication link of one of the gateway stations is affected and interrupted, Then the total capacity of the user beam is lost by 1/4. It is easy to see that the larger the number N of gateways corresponding to managing one user beam, that is, the more gateways managing one user beam at the same time, the less capacity loss of the user beam will be.

Step 3: According to the conditions of steps 1 and 2, carry out the design of the topology structure of the forward feeder branch of the HTS satellite payload.

It can be known from steps 1 and 2 that each gateway station manages multiple user sub-beams. Assuming that the frequency of the signals entering the repeater system from the feed ends of different gateway stations is F1, when passing through the microwave quadplexer, the frequency of F1 is F1. It is divided into 4 sub-bands, and the corresponding frequencies are F1-1, F1-2, F1-3, and F1-4. The bandwidth corresponding to each frequency can be adjusted. For the convenience of description, the bandwidth of the four channels after frequency division is defined to be the same. The same operation is performed on F1 entering the repeater from the feeder ends of gateway stations 2, 3, and 4 to form the forward feeder branch topology as shown in FIG. 4 .

Step 4: Design the feedforward shunt synthesis network topology.

On the basis of the forward feeder branch topology, multiple co-frequency feeder signals are distributed and recombined to synthesize multiple new F1 signals.

Each newly synthesized F1 signal is composed of feed signals from gateway stations 1, 2, 3, and 4. The specific topology is shown in Figure 5. This synthesized network is realized by a microwave hybrid bridge.

Step 5: Design the payload scheme according to the feedforward shunt synthesis network.

Specifically, as shown in Figure 6,

(51) All the user beam information received by each of the N gateway stations is divided into two parts of left-hand circular polarization and right-hand circular polarization according to different polarization modes. The information of each partially polarized user beam is filtered by a preselector and then sent to a low-noise amplifier for amplification. In order to ensure the effectiveness of the communication load and prevent the failure of the entire satellite communication due to circuit failure, a switching matrix scheme is introduced in the low-noise amplifier branch for backup protection.

(52) The amplified user beam information is then split into multiple user sub-beams through the branching network, and the number of sub-beams and the number of user beams must match each other, that is, the number of sub-beams = the number of user beams * the gateway station number N.

(53) Combining the user sub-beam information of the same frequency and the same polarization mode from different gateway stations through the branch synthesis network to form complete user beam information.

(54) The combined user beam information is subjected to frequency conversion processing through a frequency converter, and then subjected to signal amplification processing through a traveling wave tube amplifier, and then sent to the user end to complete the communication process.

Step 6: Design the branch topology of the return link of the HTS satellite payload.

Similar to step 3, each user beam includes multiple user sub-beams. Assuming that the frequencies of the signals entering the transponder system from different receiving antennas are all F1, F1 is divided into 4 sub-bands when passing through the microwave quadplexer, and the corresponding frequencies are F1-1, F1-2, F1-3, F1-4, the bandwidth corresponding to each frequency can be adjusted. Perform the same operation on user beams A, B, C, and D to form the return link branch topology as shown in FIG. 7 .

Step 7: Design the topological structure of the return link splitting synthesis network.

The topology of the return link split synthesis network is the same as that of the forward link. The signals from different user beams are first split through a multiplexer, and each beam is divided into N channels, and then the split network will repeat Allocation, the sub-beams from different users are exchanged and synthesized to form multiple new user beams F1, and then sent to different gateway stations to realize the exchange function between user beams and different gateway stations.

The reverse topology network and the forward topology network are inverse processes, as shown in FIG. 8 .

Step 8: Design the payload scheme according to the return branch synthesis network.

Specifically, as shown in Figure 9,

(81) The received user beam information is first filtered by the preselector and then sent to the low-noise amplifier for amplification. In order to ensure the effectiveness of the communication load and prevent the failure of the whole satellite communication due to circuit failure, the low-noise amplifier is introduced into the branch. Ring backup scheme for backup protection. Then, the amplified user beam information is divided into N parts through the branching network, and the user beam information of different frequencies is divided.

(82) The split sub-beams are exchanged and synthesized by frequency to form multiple user synthesized beams, and the number of synthesized beams is equal to the number of user beams.

(83) The user beam information is synthesized twice by the frequency converter and the combiner, and the combined user beam information is amplified by the amplifier, and then sent to multiple gateway stations to complete the communication process.

The content not described in detail in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims (7)

1. An HTS satellite payload radio frequency domain implementation method based on an N-active framework is characterized by comprising the following steps:

(1) determining the frequency range of a feed beam and the frequency range of a user beam according to available frequency resources provided by each downlink frequency band on an HTS satellite communication link, and designing and calculating the maximum envelope BW of the working bandwidth of a single user beam;

(2) determining that a single user beam is managed by several gateway stations in an HTS satellite communication system;

(3) designing an HTS satellite load forward feed shunt topological structure according to the conditions of the steps (1) and (2);

(4) designing a forward feed shunt synthetic network topological structure;

(5) carrying out payload scheme design according to the forward feed shunt synthetic network, which specifically comprises the following steps:

(51) dividing all user beam information received by each of N gateway stations into a left-hand circular polarization part and a right-hand circular polarization part according to different polarization modes, filtering and removing impurities of the user beam information polarized by each part through a preselector, and sending the user beam information polarized by each part into a low-noise amplifier for amplification;

(52) and splitting the amplified user beam information into a plurality of user sub-beams through a multiplexer, wherein the number of the sub-beams and the number of the user beams meet the following requirements: the number of the sub-beams is the number of the user beams and the number of the gateway stations N;

(53) combining the sub-beam information of the users with the same frequency and the same polarization mode from different gateway stations through a shunt synthesis network to form user beam information;

(54) the combined user beam information is subjected to signal amplification processing through a traveling wave tube amplifier and then is sent to a user end to complete a communication process;

(6) designing a feed shunt topological structure of an HTS satellite load return link;

(7) designing a return link shunting synthesis network topological structure;

(8) and carrying out payload scheme design according to the return link shunt synthesis network.

2. The N-active architecture-based HTS satellite payload radio-frequency domain implementation method of claim 1, characterized by: in the step (2), the single user beam is selected and managed by 2-N gateway stations together, wherein N is the total number of the gateway stations.

3. The N-active architecture based HTS satellite payload radio-frequency domain implementation method of claim 2, characterized by: the bandwidth of the single user beam is divided into N sub-bands, and the bandwidth of each sub-band is BW/N, that is, each gateway station provides a management resource with the bandwidth of BW/N for the user beam.

4. The N-active architecture based HTS satellite payload RF domain implementation method of claim 3, wherein: the step (3) of designing the HTS satellite load forward feed shunt topology specifically includes: assuming that the frequency of a user beam is F1, the user beam enters a repeater system from the feed ends of N gateway stations managing the user, and for each gateway station, F1 is divided into N sub-bands through a microwave multiplexer, and the corresponding frequencies are F1-1, F1-2, F1-3 and … F1-N respectively, so that a forward feed shunt topology is formed.

5. The N-active architecture-based HTS satellite payload radio-frequency domain implementation method of claim 1, characterized by: the forward feed shunt synthetic network topological structure or the return link shunt synthetic network topological structure is realized by adopting a microwave hybrid bridge.

6. The N-active architecture based HTS satellite payload RF domain implementation method of claim 4, wherein: the forward feed shunt synthesis network topology structure specifically comprises: on the basis of a forward feed shunt topology, N same-frequency feed signals are distributed and recombined to synthesize N new F1 signals, and each newly synthesized F1 signal is composed of feed signals from N gateway stations.

7. The N-active architecture-based HTS satellite payload radio-frequency domain implementation method of claim 1, characterized by: the method for designing the payload scheme according to the return link shunt synthetic network specifically comprises the following steps:

(71) the received user beam information is firstly filtered by a preselector and then sent to a low-noise amplifier for amplification, and then the amplified user beam information is split into N parts by a multiplexer, and the beam information of different users is split;

(72) combining the split sub-beams through a combiner according to the user attribution to form a plurality of user synthesized beams, wherein the number of the synthesized beams is equal to the number of the user beams;

(73) and carrying out secondary synthesis on the user beam information through a frequency converter and a combiner, amplifying the combined user beam information through an amplifier, and then sending the amplified user beam information to a user side to finish the communication process.

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